Evidence-based numerical building model enhancement and building energy efficiency evaluation in the case of Morocco

This paper presents a framework for numerical building validation enhancement based on detailed building specifications from in-situ measurements and evidence-based validation assessment undertaken on a detached sustainable lightweight building in a semi-arid climate. The validation process has been undergone in a set of controlled experiments – a free-float period, and steady-state internal temperatures. The validation was conducted for a complete year with a 1-min time step for the hourly indoor temperature and the variable refrigerant flow (VRF) energy consumption. The initial baseline model was improved by three series of validation steps per three different field measurements including thermal transmittance, glazing thermal and optical properties, and airtightness. Then, the accurate and validated model was used for building energy efficiency assessment in 12 regions of Morocco. This study aims to assess the effect of accurate building characteristics values on the numerical model enhancement. The initial CV(RMSE) and NMBE have improved respectively from 14.58 % and −11.23 %–7.85 % and 1.86 % for the indoor temperature. Besides, from 31.17 % to 14.37 %–20.57 % and 9.77 % for energy consumption. The findings demonstrate that the lightweight construction with the use of a variable refrigerant flow system could be energy efficient in the southern regions of Morocco

Nonaqueous capillary electrophoresis-electrospray- mass spectrometry for the analysis of fluoxetine and its related compounds

The potential of nonaqueous capillary electrophoresis was investigated for the simultaneous separation of fluoxetine hydrochloride, its meta-isomer, and other related compounds. The resolution of these compounds was compared in aqueous and nonaqueous media. Baseline separation of the studied solutes required a buffer electrolyte solution composed of 25 mM ammonium acetate and 1 M acetic acid in acetonitrile, an applied voltage of 30 kV and a temperature of 20 degrees C. Selectivity was considerably affected by the nature of the solvent (water, methanol, and acetonitrile). Moreover, substituting acetate by formate in the background electrolyte resulted in migration time changes, which were attributed to an ion-pairing phenomenon. Finally, the method was successfully coupled on-line with electrospray ionization-mass spectrometry (ESI-MS) and allowed significant selectivity and sensitivity enhancement. The effect of ESI-MS parameters, such as nebulizing gas pressure, sheath liquid composition and flow rate, on resolution and method sensitivity was also discussed

Micellar and microemulsion electrokinetic chromatography of selected anesthetic drugs

A microemulsion electrokinetic chromatography method is described for the simultaneous analysis of local anesthetic drugs, including lidocaine, mepivacaine, bupivacaïne, cinchocaine, cocaine, prilocaine, and ketamine. The effect of the microemulsion composition such as SDS concentration, octane and 1-butanol percentages, as well as the separation temperature, on the electrophoretic behavior of the investigated drugs is described. Results show that the migration window is mainly affected by the SDS concentration in the microemulsion buffer. Adequate separation was performed with an uncoated fused silica capillary (48.5 cm total length x 50 μm ID) and a microemulsion buffer consisting of 50 mM octane, 80 mM sodium dodecyl sulfate, 800 mM 1-butanol, and 10 mM borate buffer (pH 9.0). Retention factors of the investigated anesthetic drugs were highly correlated with the octanol-water partition coefficients. Finally, separation characteristics in MEEKC were compared to those obtained in MEKC under similar micellar conditions. Results indicate the superiority of microemulsion pseudo-phases in terms of selectivity and separation window control

Use of negatively charged cyclodextrins for the simultaneous enantioseparation of selected anesthetic drugs by capillary electrophoresis-mass spectrometry

The simultaneous enantioseparation of selected anesthetic drugs was studied by capillary electrophoresis (CE) in presence of three different negatively charged cyclodextrins (CDs). Among the chiral selectors tested, namely carboxymethyl, sulfobutyl ether and sulfated-beta-CD, the latter appeared to be the most effective to achieve the enantiomeric resolution of the investigated compounds. Beside CD type, resolution was greatly influenced by the buffer pH, the molecular structure of the anesthetic compounds, CD concentration and temperature. The optimum electrophoretic conditions for the stereoselective analysis of the studied anesthetics were obtained with a poly(vinyl alcohol) coated capillary (48.5 cm total length x 50 microm I.D.), a 50 mM Tris-phosphate buffer at pH 2.5 containing 6 mg ml(-1) of sulfated-beta-CD, an applied voltage of 30 kV and a temperature of 30 degrees C. Under these optimized conditions, four drugs, namely bupivacaine, mepivacaine, ketamine and prilocaine, were simultaneously enantioresolved in less than 12 min. Furthermore, the method was applied to the stereoselective analysis of mepivacaine in a pharmaceutical preparation. Finally, the method was on-line coupled to electrospray ionization mass spectrometry using the counter current partial-filling technique

Separation of selected anesthetic drugs by nonaqueous capillary electrophoresis

The potential of nonaqueous capillary electrophoresis was investigated for the separation of selected anesthetic drugs. The effect of parameters, such as methanol-acetonitrile composition, temperature, apparent pH* and ionic strength of the electrophoretic media on migration times and selectivity was discussed. The capillary electrophoresis separation of these drugs was compared in aqueous and nonaqueous media. The best separation was achieved with a fused silica capillary (48.5 cm total length x 50 mm I.D.), a buffer electrolyte solution composed of 25 mM ammonium acetate in methanol, an applied voltage of 30 kV and a temperature of 10 oC. Replicate injections under the optimal nonaqueous conditions gave acceptable precision data for migration times and peak areas

Optimal Integral Super-Twisting Sliding-Mode Control for high efficiency of Pumping Systems

International audienc

Improving High Efficiency and Reliability of Pump Systems using Optimal Fractional-order Integral Sliding-Mode Control Strategy

International audienceIn this paper, a robust optimal efficiency controller for a complete water pumping system is designed based on the Fractional order Integral Sliding Surface (FISMC) with Linear Quadratic Regulator (LQR) related to the Minimum Electric Loss (MEL) condition. The developed model's novelty is based on a strategy to improve the control's performance robustness with optimal costs, in which a compromise is made between minimizing electric motor power losses and accurate flow rate adjustment in order to operate the pump at its best efficiency point and increase discharge flow rate stability for more flexibility against frequently changing working conditions. The whole system is simulated in MATLAB SIMULINK workspace, and a comparative analysis based on control energy, chattering phenomena, stability and control robustness has been conducted between the conventional PI, LQR, Integral Super-Twisting Sliding Mode Surface (ISTSMC) and the proposed control strategy MEL-FISMC-LQR. Finally, we evaluated the performance of the designed controls, including the Integral Absolute Error (IAE). The simulation results show that the proposed control design significantly improves pumping system efficiency and stabilizes the discharge flow rate at each operation point of the pumping system, and also improves flexibility against variable-speed and throttling valve. Furthermore, the stability of the closed-loop control system is assured by Lyapunov approach, and dynamic performance regardless of external disturbances as well as unknown uncertainties and parameter variations

Nonaqueous capillary electrophoresis-mass spectrometry for separation of venlafaxine and its phase I metabolites

Aqueous and nonaqueous capillary electrophoresis (NACE) were investigated for separation of venlafaxine, a new second-generation antidepressant, and its three phase I metabolites. Working at basic pH, around the venlafaxine pKa value, was effective in resolving the investigated drugs, but created considerable peak tailing. To overcome electrostatic interactions between analytes and silanol groups, investigations were also carried out at acidic pH. However, despite the addition of up to 50% v/v of organic solvents (e.g., methanol or acetonitrile), complete separation of the studied compounds was not possible. NACE was found to be an appropriate alternative to resolve venlafaxine and its metabolites simultaneously. Using a conventional capillary (fused-silica, 64.5 cm length, 50 microm inner diameter), and a methanol-acetonitrile mixture (20/80 v/v) containing 25 mM ammonium formate and 1 M formic acid, complete resolution of these closely related compounds was performed in less than 3.5 min. Selectivity, efficiency and separation time were greatly affected by the organic solvent composition. As the electric current generated in nonaqueous medium was very low, the electric field was further increased by reducing the capillary length. This allowed a baseline resolution of venlafaxine and its three metabolities in 0.7 min. Selectivity was compared in aqueous and nonaqueous media in relation to the acid-base properties of the analytes as well as to the solvation degree. Finally, the method successfully coupled on-line to mass spectrometry with electrospray ionization interface allowed significant sensitivity enhancement